The invention relates to a method for determining a power consumption in an electrical installation comprising a group of several individual electricity distribution branches between several loads, and an incoming main line connecting the group of branches to an electrical power supply. The method in question is of a type according to which it comprises the action of performing in time and of recording measurements taken on the incoming main line and enabling the overall power consumed by the group of branches to be established.
The invention also relates to a monitoring system of a group of several individual electricity distribution branches between several loads in an electrical installation, of the type comprising at least:                a device for performing measurements on an incoming main line connecting the group of branches to an electrical power supply,        a memory for storing these measurements which enable the overall power consumed by the group of branches to be established,        an equipment transducer of a specific branch among the branches.        
The invention further relates to an electrical installation of the type comprising a group of several individual electricity distribution branches between several loads, an incoming main line connecting the group of branches to an electrical power supply.